This invention relates to a circuit board structure with increased edge connection capacity.
It is common practice to make electrical connections between circuitry on a printed circuit board and a power supply or an external signal source or signal destination by mechanically engaging a connection edge of the board with a mating receptacle and simultaneously establishing electrically conductive connections between an electrically conductive structure at the connection edge of the board and a complementary electrically conductive structure incorporated in the receptacle and including contacts that are electrically connected to the power supply or to the signal source or destination, as the case may be. In one conventional case, the receptacle and electrically conductive structure incorporated therein is known as a card edge connector and the conductive structure at the connection edge of the circuit board is a printed pattern of conductive strips. It is possible to provide connections at a density as high as 38 pins per inch of circuit board edge with this type of connection scheme.
It is not always convenient or desirable to employ a card edge connector for connecting circuitry on a printed circuit board with circuitry off the circuit board, and in some cases it may be necessary or desirable to employ coaxial connectors, such as the connectors that are commonly known as BNC connectors. For example, in one application where BNC receptacles are provided in a backplane assembly of a mounting frame and it is necessary to provide electrical connection between the BNC receptacles and circuitry on a circuit board that slides into the frame, it has been found desirable to provide BNC receptacles along the connection edge of the circuit board and to implement the BNC receptacle in the backplane assembly with the female portion of a male/female BNC feed through. When the circuit board is installed in the frame, a receptacle on the connection edge of the board engages the male portion of the feed through.
When BNC receptacles are used in this manner, the minimum center-to-center spacing of the receptacles is about 0.625 inches and accordingly the maximum density of signal paths that can be provided along the connection edge of the circuit board is much less than in the case of the other conventional scheme mentioned above. If in order to maximize the number of signal paths, the maximum number of BNC receptacles are mounted to the circuit board at its connection edge, there is little space for other connections, for example for power lines and control signals.
In accordance with a first aspect of the invention there is provided electronic equipment comprising a frame including a wall and connectors attached to the wall of the frame, a main board having a connection edge at which it is provided with connectors for engaging the connectors that are attached to the wall of the frame when the main board is advanced relative to the frame along a connection axis, an edge connector receptacle attached to the wall of the frame and defining a slot perpendicular to the connection axis and to the connection edge of the main board, and an auxiliary board attached to the main board and oriented perpendicular to the main board and parallel to the connection axis and having a connection edge perpendicular to the connection edge of the main board, the auxiliary board being positioned to enter the slot of the edge connector receptacle concurrently with engagement of the connectors at the connection edge of the main board with the connectors attached to the wall of the frame.
In accordance with a second aspect of the invention there is provided electronic equipment comprising a frame including a wall and connectors attached to the wall of the frame, a main board having a connection edge at which it is provided with connectors for engaging the connectors that are attached to the wall of the frame when the main board is advanced relative to the frame along a connection axis, first and second edge connector receptacles attached to the wall of the frame and each defining a slot perpendicular to the connection axis and to the connection edge of the main board, the connectors that are attached to the frame being between the first and second edge connector receptacles, and first and second auxiliary boards attached to the main board and each oriented perpendicular to the main board and parallel to the connection axis and having a connection edge perpendicular to the connection edge of the main board, the first and second auxiliary boards being positioned to enter the slots of the first and second edge connector receptacles respectively, concurrently with engagement of the connectors at the connection edge of the main board with the connectors attached to the wall of the frame.